third_party/llvm-project/libcxx/test/std/utilities/utility/mem.res/mem.poly.allocator.class/mem.poly.allocator.mem/construct_pair.pass.cpp

//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

// UNSUPPORTED: c++03, c++11, c++14
// XFAIL: availability-pmr-missing

// <memory_resource>

// template <class T> class polymorphic_allocator

// template <class U1, class U2>
// void polymorphic_allocator<T>::construct(pair<U1, U2>*)

#include <memory_resource>
#include <cassert>
#include <tuple>
#include <type_traits>
#include <utility>
#include "uses_alloc_types.h"

int constructed = 0;

template <int>
struct default_constructible {
  default_constructible() : x(42) { ++constructed; }
  int x = 0;
};

int main(int, char**) {
  // pair<default_constructible, default_constructible>
  {
    typedef default_constructible<0> T;
    typedef std::pair<T, T> P;
    typedef std::pmr::polymorphic_allocator<void> A;
    alignas(P) char buffer[sizeof(P)];
    P* ptr = reinterpret_cast<P*>(buffer);
    A a;
    constructed = 0;
    a.construct(ptr);
    assert(constructed == 2);
    assert(ptr->first.x == 42);
    assert(ptr->second.x == 42);
  }

  // pair<default_constructible<0>, default_constructible<1>>
  {
    typedef default_constructible<0> T;
    typedef default_constructible<1> U;
    typedef std::pair<T, U> P;
    typedef std::pmr::polymorphic_allocator<void> A;
    alignas(P) char buffer[sizeof(P)];
    P* ptr = reinterpret_cast<P*>(buffer);
    A a;
    constructed = 0;
    a.construct(ptr);
    assert(constructed == 2);
    assert(ptr->first.x == 42);
    assert(ptr->second.x == 42);
  }

  return 0;
}